Phenolic acids are a group of plant-based phytochemicals found abundantly in fruits, vegetables, coffee, and whole grains. They include compounds such as ferulic acid, caffeic acid, and gallic acid. Scientific studies have shown that phenolic acids possess antioxidant, anti-inflammatory, and vasoprotective properties, which can contribute to the maintenance and support of capillary health.

Research indicates that the antioxidant activity of phenolic acids helps protect endothelial cells that line blood vessels, including capillaries, from oxidative stress and inflammation. By neutralizing free radicals, phenolic acids may prevent damage to the capillary walls and improve microcirculation. Some animal and in vitro studies suggest that these compounds can enhance capillary resistance and reduce vascular permeability, which are important for preventing capillary fragility and associated conditions such as easy bruising or edema.

While most evidence comes from laboratory and animal studies, there are some small human studies and epidemiological data linking higher dietary intake of phenolic acid-rich foods to better vascular health. However, the direct clinical evidence for supplementation of isolated phenolic acids specifically to support the capillary system remains limited. Overall, phenolic acids are considered beneficial for vascular health, including the capillaries, but more targeted clinical trials are needed to strengthen the evidence base.